Method of making insulator caps



1,636,586 Ju y 19, H. BARNES METHOD OF N NG INSULATOR CAPS Filed Dec. 192$ 3 Sheets-Sheet l g'rvwzwtoz Fig.5

55% fZL.Bar/2w 1,636,586 y 1927- H. 1.. BARNES METHOD OF MAKING INSULATOR CAPS Filed Dec. 2. 1925 3 SheetsSheet 2 1927. July H. BARNES METHOD OF MAKING INSULATOR GAPS Filed-Dec.

2. 1925 3 Sheets-Sheet 5 314 021 Mo t Fatented duly l9), E927.

UNTTETJB STATES HERMAN 1L. EARNESd, 0F CANTON, OHIG,

ASSIGNOR T0 THE AMERICAN FORGE & MA-

CKENZIE, CQBEPANY, 01E CANTON, QHIO, A. CGRIORATION OF OHIO.

METHQD 0F MAKING- INSULATUR CAPS.

application filedfiecembera, 1926. Serial No. 152,232.

socket joint, in order that the cap may freely.

oscillate on the suspending shank.

The ball of the joint is usually at the lower end of the shank, and it is removably fitted with a dome socket in the head of the insulator cap.

Tt has heretofore been a usual practice to forge or form an insulator cap having a solid head, and to machine cut the dome socket in the head. In addition to the waste of material caused by cutting the socket in the head, the dome socket having undercut walls, and in a preferred form having protruding lugs therein, is exceedingly difficult to cut by ordinary machining operations.

Accordingly the object of the present improvements is to provide a method for direct forming as by forging dome sockets for making separable ball and socket joints in insulater caps,

The object is attained in improved method hereina in detail, and which ma be stated in general terms as including rst, forming as by forging a scalloped straight or outwardly flaring cup in the head of an insulator cap, and then pressing the scalloped cup Walls inweirdly to form the desired dome socket for the ball and socket joint.

The preferred form of insulator caps and 1 carrying out the ter to be set forth the improved method of making the same are illustrated in the accompanying drawings forming part hereof, in which Figure 1, is a fragmentary elevation view with the insulator cap in axial cross section,

till

illustrating the improved cap in combination with a suspending shank and an insulator; Fig. 2, a fragmentary sectional view of the dies and cap illustrating the first step in the im roved method;

ig. 3, a similar view illustrating the second or pressing step in the improved method;

Fig. 4, a vertical axial sectional view, as on line M, Fig. 5, of one of the improved insulator caps after the first step in the dome socket forming operations;

Fig.6, a top plan View thereof;

Fig. 6, a vertical axial sectional view, as on line 6-6, Fig. 7,-of one of the insulator caps after the final or dome pressing socket forming operations; and

Fig. a top plan view thereof.

Similar numerals refer to similar parts throughout the ,drawings.

The insulator cap illustrated in Fig. 1, and indicated generally at 10 includes an upper head 11 and a lower bell 12 which may be internally grooved adjacent its lower edge as at 13 for securing the head 14 of an sulator.

The insulator cap head 11 is preferably provided with an internal domesocket 15 adapted for removably receiving through an irregular aperture 16, the deformed ball lower end 17 of a suspending shank 18, the upper end 19 of which may be secured by any well known means to the cross arm or pike like of a transmission line tower or the The ball 17 is secured in the dome socket 15 as b means of a cotter pin 20 which passes t rough opposite laterally extending apertures 21 in the lower portions of the head dome Wall 22, beneath the end of the ball end 17.

Guide lugs 23 protrudin upward from. the inner surface 24 of the dome socket bottom, at one side thereof beneath the head of the irregular aperture, assist the cotter pin in maintaining the ball in the socket joint, and also operate as cams a ainst the ball head when the same is inserted into the dome socket through the aperture 16,

It has been customary to form the irregular aperture 16, and the dome socket 1.5 in the head of a forged insulator cap, by first forging a solid hemispherical head, and then machine cutting therein the irregular aperture, and the dome socket.

This method of making the insulator caps is wasteful of material and labor, and necessitates very diflicult machining operations.

BK carrying out the method herein set fort the irregular aperture, the dome till Ell

socket, and also the lugs therein may be direct-ly formed as by forging in the head 11 of the insulator cap. I

This improved method includes first forming as by forging in a semifinished insulator cap indicated generally at 10 in Figs. 4 and 5, a head 11 including an upper cup 15 having a tapered tubular side wall 22 and an upper scalloped edge 16 therefor, and lugs 23 in the cup protruding upward from the bottom wall 24.

The forming of such an upper cup may be carried out by forging as illustrated in Fig. 2, as by means of as lower supporting die 25, an upper cupping and scalloping die 26, and suitable side supports 27, all of which may be operated in any well known manner, as in a drop hammer, bulldozer, upsetter, or the like.

After the cup 15 has been formed in the head 11 as illustrated in Fig. 2, the cup walls 22 are pressed inwardly as by means of a pressing die 26' having a hemispherical depression 28 therein which strikes upon the scalloped edges and outer surfaces of the cup 22 and presses the tubular cup wall inwardly to form the desired dome socket l5, and aperture 16, as illustrated in Fig. 3.

The tapered form of the tubular cup wall 22' facilitates the inward pressing thereof to form the finished product.

The scalloping of the upper edge of the upper cup to a predetermined form, automatically shapes the irregular aperture for the dome socket when the cup walls areinwardly pressed.

While it is preferred to carry out the fore gomg method as a hot forging method, in which both dome socket forming operations are performed upon hot metal, it is possible.

to form the cup 15' by any desired means, and to cold press the tubular cup wall inwardly to form the desired dome socket 15.

I claim: 1. The method of making an insulator cap or the like, which includes forming by forging means a cup having a tubular wall, and

. inwardly pressing the tubular wall to form a'.

dome socket.

2. The method of making an insulator cap or the like, which includes forming by forging means a cup having a tubular wall and ing means a cup ha'ving a tapered tubularwall and a scalloped outer edge therefor, and inwardly pressing the tapered tubular wall to form a dome socket having an irregular aperture in its domewa'll'.

5. The method of making an insulator cap or the like, which includes forming by forging means a cup having guide lugs protruding upward, from the inside surface of its bottom and a tubular wall extending from the bottom, and inwardly pressing the tubu lar wall to form a dome socket.

6. The method of making an insulatorcap or the like, which includes forming by forging means a cup having guide lugs protrud ing upward from the inside surface of its bottom and a tubular wall havin a scalloped outer edge extending from th bottom, and inwardly pressing the tubular wall to form a dome socket having an irregular aperture in its dome wall.

7. The method of making an insulator cap or the like, which includes forming by forging means a cup having guide lugs protruding upward from the inside surface of its bottom and a tapered tubular wall extending from the bottom, and inwardly pressing the tapered tubular wall to form a dome socket.

8. The method of making an insulator cap or the like, which includes forming by forging means a cup having guide lugs protruding upward from the inside surface of its bottom and a tapered tubular wall having a hereunto subscribed my name.

HERMAN L. BARNES. 

